Table of Contents
Definition / general | Radiology description | Radiology images | Case reports | Treatment | Gross description | Gross images | Microscopic (histologic) description | Microscopic (histologic) images | Cytology images | Positive stains | Electron microscopy description | Differential diagnosis | Additional referencesCite this page: Giant cell tumor. PathologyOutlines.com website. http://www.pathologyoutlines.com/topic/bonegiantcelltumor.html. Accessed July 14th, 2017.
Definition / general
- Also called osteoclastoma
- Benign but locally aggressive neoplasm with large numbers of osteoclast-like giant cells in background of epithelioid to spindle shaped mononuclear cells
- Ages 20 - 40 years; 55% women, more common in Oriental countries
- Associated with Paget disease of bone
- Giant cells appear to be due to fusion of circulating monocytes; stromal cells appear to be neoplastic and may originate from mesenchymal stem cells that reside in bone marrow (Hum Pathol 2003;34:983)
- Question diagnosis if tumor is in a child, lesion is in metaphysis or diaphysis of long bone, multiple lesions (unless patient has Goltz syndrome), lesion in nonsacral vertebrae, jaw of non Paget patient or hands / feet
- Sites: knee is common site (distal femur, proximal tibia), distal radius, sacrum but can affect any bone, usually at epiphysis, may spread into metaphysis; uncommon in hand / feet, jaw, vertebrae other than sacrum
Radiology description
- Lytic, expansile lesion of epiphysis extending to articular cartilage, usually without peripheral bone sclerosis, periosteal reaction or mineralization within the lesion
- Within soft tissues usually produces eggshell ossification at periphery
Radiology images
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Case reports
- 21 year old woman with anaplastic-like changes in sacral tumor after preoperative embolization (Arch Pathol Lab Med 1999;123:163)
- 36 year old man with rib tumor (Arch Pathol Lab Med 2004;128:452)
Treatment
- Surgical curettage (34% recur) or en bloc excision (7% recur); may implant into adjacent soft tissue; radiation therapy only if surgical excision impossible since it may promote malignant transformation
- Course: low grade malignancy; metastasis to lung or lymph nodes (1 - 2%) associated with cortex interruption; have similar benign microscopic appearance; good prognosis if remove metastasis; may die of tumor if diffuse metastases
Gross description
- Large, peripheral expansile lesion, well circumscribed, hemorrhagic / red brown, cystic with necrosis
- Thinned cortex
- May appear fleshy white or pink or yellow in areas of foam cells
Gross images
Microscopic (histologic) description
- Regular and uniform distribution of stromal cells and giant cells
- Stromal cells are mononuclear, resemble macrophages
- Giant cells are large, multinucleated (10 - 50 nuclei) with similar nuclei as stromal cells, resemble osteoclasts
- Necrosis, hemorrhage, hemosiderin, reactive bone
- Mitotic figures (not atypical)
- 1 / 3 have focal deposition of osteoid or bone
- May have aneurysmal bone cyst component, foam cells with spindling of mononuclear cells
- No chondroid differentiation, no atypia
Microscopic (histologic) images
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Positive stains
- Giant cells: acid phosphatase, lysozyme, alpha-1-antitrypsin, alpha-1-antichymotrypsin, cyclin D1, estrogen receptor (50%, Hum Pathol 2002;33:165)
- Mononuclear cells: Ki67
Electron microscopy description
- Giant cells have ruffled border and abundant mitochondria (resemble osteoclasts)
- Viral-like and other intranuclear inclusions, some similar to Pagets disease of bone
Differential diagnosis
- Other giant cell tumors usually have only focal giant cells
- Aneurysmal bone cyst
- Brown tumor of hyperparathyroidism
- Chondroblastoma
- Chondromyxoid fibroma
- Giant cell granuloma
- Langerhans cell histiocytosis
- Metaphyseal fibrous defect / nonossifying fibroma
- Osteoblastoma
- Osteoid osteoma
- Osteosarcoma
- Pigmented villonodular synovitis
- Solitary bone cyst
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